For those unfamiliar with the Urim and Thummim, I was thinking that a little background might help.

Urim comes from the Hebrew uwriym, which is the plural of uwr, meaning light, flame, or fire.  Uwr is from the root word owr, which means:  ‘to be or to make luminous; break of day; to give or show light; to be enlightened; to shine, or to set on fire.’

Urim literally means lights.

Thummim is from the Hebrew Tummiym, which is the plural of tom, meaning: ‘completeness; innocence; integrity; perfect, or uprightness.’  Tom is derived from the root word tamam, which means: ‘to complete in a [positive or negative] sense; to be perfect.’

Thummim literally means perfections or complete truth.

The words are translated various ways in different versions of scripture:  ‘Lights and Perfections’ ‘Light and Truth’ ‘Manifestation and Truth’ and ‘The Sacred Lots.’

The Urim and Thummim represent counsel, guidance [to determine order of priests] decisions, to receive answers.  The use of them were a right of the priesthood, to give counsel and direction from God.  They also represent judgement.

(See Exodus 28:30)